Nuclide transmutation device and nuclide transmutation method

ABSTRACT

The present invention produces nuclide transmutation using a relatively small-scale device. The device  10  that produces nuclide transmutation comprises a structure body  11  that is substantially plate shaped and made of palladium (Pd) or palladium alloy, or another metal that absorbs hydrogen (for example, Ti) or an alloy thereof, and a material  14  that undergoes nuclide transmutation laminated on one surface  11 A among the two surfaces of this structure body  11.  The one surface  11 A side of the structure body  11,  for example, is made a region in which the pressure of the deuterium is high due to pressure or electrolysis and the like, and the other surface  11 B side, for example, is a region in which the pressure of the deuterium is low due to vacuum exhausting and the like, and thereby, a flow of deuterium in the structure body  11  is produced, and nuclide transmutation is carried out by a reaction between the deuterium and the material  14  that undergoes nuclide transmutation.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a nuclide transmutation deviceand a nuclide transmutation method associated, for example, withdisposal processes in which long-lived radioactive waste is transmutedinto short-lived radioactive nuclides or stable nuclides, andtechnologies that generate rare earth elements from abundant elementsfound in the natural world.

[0003] 2. Description of the Related Art

[0004] Conventional disposal processes are known that include, forexample, methods in which large amounts of long-lived radioactivenuclides included in high level radioactive waste and the like areefficiently and effectively transmuted in a short time. Examples ofthese methods are those in which small amounts of nuclide aretransmuted, such as heavy element synthesis by a nuclear fusion reactionusing a heavy ion accelerator.

[0005] These disposal processes are nuclide transmutation processes inwhich minor actinides such as Np, Am, and Cm included in high levelradioactive waste, long-lived radioactive products of nuclear fissionsuch as Tc-99 and I-129, exothermic Sr-90 and Cs-137, and usefulplatinum group elements such as Rh and Pd are separated depending on theproperties of each of the elements (group separation), and subsequentlycausing a nuclear reaction by desorption of neutrons, the minoractinides having a long half-life and nuclear fission products, andtransmuted into short-lived radioactive or non-radioactive nuclides. Inaddition, the useful elements and the long-lived radioactive nuclidesincluded in the high level radioactive waste are separated andrecovered, effective use of the elements is implemented, and at the sametime, long-lived radioactive nuclides are transmuted into short-livedradioactive or stable nuclides.

[0006] Three types of disposal processing methods are known: disposalprocessing for actinides and the like by neutron irradiation in anuclear reactor such as a fast breeder reactor or an actinide bumreactor; nuclear spallation processing for actinides and the like byneutron irradiation in an accelerator, and disposal processing ofcesium, strontium, and the like by gamma ray irradiation in anaccelerator.

[0007] By neutron irradiation in a nuclear reactor, minor actinides,which have a large neutron interaction cross-section, can be rationallyprocessed, and in particular, by irradiation with fast neutrons,transuranic elements, whose nuclear fission is difficult to cause, canbe directly caused to undergo nuclear fission.

[0008] However, long-lived radioactive nuclear fission products aredifficult to process by neutron irradiation in a nuclear reactor and thelike, and for example, for Sr-90, Cs-1137 and the like, which have asmall neutron interaction cross section, disposal processing using anaccelerator is applied.

[0009] In a disposal process using an accelerator, because unlike anuclear reactor they are operated subcritically, the safety in relationto criticality is superior, and there is the advantage that there is alarge degree of design freedom, and proton accelerators and electronbeam accelerators are used.

[0010] In disposal processing using a proton accelerator, a nuclearspallation reaction is used in which high energy protons at, forexample, 500 MeV to 2 GeV, are irradiated to spall the target nucleus,and nuclide transmutation is caused directly by using the nuclearspallation reaction. In addition, a nuclear fission reaction isgenerated by injecting the plurality of neutrons generated along withspallation of the target nucleus into a subcritical blanket placedaround the target nuclei, and a nuclide transmutation reaction isgenerated by a neutron capture interaction. Thereby, for example,transuranic elements such as neptunium and americium and long-livedradioactive nuclear fission products can be disposed of, andfurthermore, the heat generated by the subcritical blanket can berecovered and used for power generation, and the power necessary tooperate to the proton accelerator can be made self-sufficient.

[0011] In addition, in disposal processing using an electronaccelerator, disposal processing of long-lived radioactive nuclearfission products such as strontium and cesium and the transuranicelements and the like can be carried out by using gamma radiationgenerated by the bremsstrahlung of the proton beam or a large resonancereaction such as a photonuclear reaction, for example, the (γ, N)reaction and the (γ, nuclear fission) reaction, using gamma radiationand the like generated by a reverse Compton scattering by combining, forexample, an electron accumulating ring and an optical cavity.

[0012] However, in the case of carrying out nuclide transmutation usinga nuclear reactor or an accelerator, as in the disposal processes in theabove-described examples of conventional technology, there are theproblems in that large-scale and high cost apparatuses must be used, andthe cost required for the nuclide transmutation increases drastically.

[0013] Furthermore, in the case of processing, for example, Cs-137,which is a long-lived radioactive nuclide fission product, whentransmutating Cs-137 radiated from an electron power generator of aboutone million KW to another nuclide using an accelerator, there areproblems in that the necessary power reaches one million KW and a highstrength and large current accelerator become necessary, and thusefficiency is low.

[0014] In addition, in contrast to a thermal neutron flux of about1×10¹⁴/cm²/sec in a nuclear reactor such as a light water reactor, theneutron flux necessary for nuclide transmutation of Cs-137, which has asmall neutron interaction cross section, is about 1×10¹⁷-1×10¹⁸/cm²/sec,and there is the problem in that the necessary neutron flux cannot beattained.

SUMMARY OF THE INVENTION

[0015] In consideration of the above-described circumstances, it is anobject of the present invention to provide a nuclide transmutationdevice and a nuclide transformation method that can carry out nuclidetransmutation with a relatively small-scale device compared to thelarge-scale devices such as accelerators and nuclear reactors.

[0016] In order to attain the object related to solving the problemsdescribed above, the nuclide transmutation device according to a firstaspect of the invention comprises a structure body (the structure body11, the multilayer structure body 32, the cathode 72, the multilayerstructure body 89, the multilayer structure body 102 in the embodiments)that is made of palladium or a palladium alloy, or a hydrogen absorbingmetal other than palladium, or a hydrogen absorbing alloy other than apalladium alloy, an absorbing part (the absorbing chamber 31, theabsorbing chamber 103, or the electrolytic cell 83 in the embodiments)and a desorption part (the desorption chamber 34, the desorption part101, or the vacuum container 85 in the embodiments) that are disposed soas to surround the structure body on the sides and form a closed spacethat can be sealed by the structure body, a high pressurization device(the deuterium tank 35, the deuterium tank 106, or the power source 81in the embodiments) that makes the absorption part side on the side ofthe surface of the structure body have a state wherein the pressure ofthe deuterium is relatively high, a low pressurization device (theturbo-molecular pumps 38 and 110, the rotary pumps 39 and 111, and avacuum exhaust pump 91 in the embodiments) that makes the desorptionpart side on the other side of the surface of the structure body have astate wherein the pressure of the deuterium is relatively low, and atransmutation material binding device (the step S22, the step S44, orthe step S04 a, in the embodiments) that binds the material thatundergoes nuclide transmutation on one surface of the structure bodymaterial (¹³³Cs, ¹²C, and ²³Na in the embodiments) that undergoesnuclide transmutation on the one of the surface of the structure body.

[0017] According to the nuclide transmutation device having thestructure described above, a pressure differential in the deuteriumbetween the one surface and the other surface of the structure body isprovided in a state wherein the material that undergoes nuclidetransmutation is bound to one of the surfaces of the structure bodyserving as a multilayer structure, and within the structure body a fluxof deuterium from one surface side to the other surface side isproduced, and thereby an easily reproducible nuclide transmutationreaction can be produced for the deuterium and the material thatundergoes nuclide transmutation.

[0018] Furthermore, the nuclide transmutation device according to asecond aspect of the present invention is characterized in comprising ahigh pressurization device that provides a deuterium supply means (thedeuterium tanks 35 and 106 in the embodiments) that supplies deuteriumgas to the absorption part, and the low pressurization device providesan exhaust means (the turbo-molecular pumps 38 and 10, and the rotarypumps 39 and 111 in the embodiments) that brings about a vacuum state inthe desorption part.

[0019] According to the nuclide transmutation deice having the structuredescribed above, the absorption part is pressurized by the deuteriumsupply device, and at the same time, the pressure in the radiation partis reduced to a vacuum state by the exhaust means, and thus a pressuredifferential in the deuterium is formed in the structure body.

[0020] Furthermore, the nuclide transmutation device according to athird aspect is characterized in the high pressurization deviceproviding an electrolysis device (the power source 81 in theembodiments) that supplies an electrolytic solution (the electrolyticsolution 84 in the embodiments) that includes deuterium to theabsorption part and electrolyzes the electrolytic solution with thestructure body serving as the cathode, and the lower pressurizationdevice provides an exhaust device (the vacuum exhaust pump 91 in theembodiments) that brings about a vacuum state in the radiation part.

[0021] According to the nuclide transmutation device having thestructure described above, by electrolyzing the electrolytic solution onone surface of the structure body with the structure body serving as acathode, deuterium is absorbed effectively into the structure body dueto the high pressure, and by reducing the pressure of the radiation partto a vacuum state using the exhaust device, a pressure differential inthe deuterium is formed in the structure body.

[0022] Furthermore, the nuclide transmutation device according to afourth aspect of the present invention is characterized in thetransmutation material binding device providing a transmutation materiallamination device (step S04, step S44, or step S04 a, in theembodiments) that laminates the material that undergoes nuclidetransmutation onto one surface of the structure body.

[0023] According to the nuclide transmutation device having thestructure described above, the transmutation material lamination meanscan laminate the material that undergoes the nuclear transmutation onone surface of the structure body by a surface forming process, such aselectrodeposition, vapor deposition, or sputtering.

[0024] Furthermore, the nuclide transmutation device according to afifth aspect of the present invention is characterized in thetransmutation material binding device providing a transmutation materialsupply means (step S22 in the embodiments) that supplies a material thatundergoes nuclide transmutation in the absorption part, and exposing onesurface of the structure body to a gas or liquid that includes thematerial that undergoes the nuclide transmutation.

[0025] According to the nuclide transmutation device having thestructure described above, the material that undergoes nuclidetransmutation can be bound to one surface of the structure body bymixing the material that undergoes nuclide transmutation in, forexample, a gas or liquid that includes deuterium.

[0026] Furthermore, the nuclide transmutation device according to thesixth-aspect of the present invention is characterized in that thestructure body provides from one surface to the other surface in order abase material (the Pd substrate 23 in the embodiments) that is made ofpalladium or a palladium alloy, or a hydrogen absorbing metal other thanpalladium, or a hydrogen absorbing alloy other than a palladium alloy; amixed layer (the mixed layer 22 in the embodiments) that is formed onthe surface of the base material and comprises palladium or a palladiumalloy, or a hydrogen absorbing metal other than palladium or a hydrogenabsorbing alloy other than a palladium alloy, and a material having alow work function (CaO in the embodiments); and a surface layer (the Pdlayer 21 in the embodiments) that is formed on the surface of the mixedlayer and comprises palladium or a palladium alloy, or a hydrogenabsorbing metal other than palladium or a hydrogen absorbing alloy otherthan a palladium alloy.

[0027] According to the nuclide transmutation device having thestructure described above, a mixed layer that includes a material havinga low work function is provided on the structure body that serves as themultilayer structure, and thereby the repeatability of the production ofthe nuclide transmutation reaction is improved.

[0028] According to the nuclide transmutation device having thestructure described above, the production of the nuclide transmutationreaction can be further promoted by transmuting the material thatundergoes nuclide transmutation to a nuclide having a similar isotoperatio composition.

[0029] In addition, the nuclide transmutation method according to aseventh aspect of the present invention is characterized in including inthe structure body (the structure body 11, the structure body 32,multilayer structure body 32, the cathode 72, the multilayer structurebody 89, and multilayer structure body 102 in the embodiments)comprising palladium or a palladium alloy, or a hydrogen absorbing metalother than palladium, or a hydrogen absorbing alloy other than apalladium alloy, a high pressurizing process (step S07, step S25, orstep S46 in the embodiments) that brings about a state in which thepressure of the deuterium is relatively high on one surface side of thestructure body, a low pressurizing process (step S05, step S23, or stepS45 in the embodiments) that brings about a state in which the pressureof the deuterium is relatively low on the other surface side of thestructure body, and a transmutation material binding process (step S04and step S22 or steps S44 and S04 a in the embodiments) that binds thematerial that undergoes nuclide transmutation to the one surface of thestructure body.

[0030] According to the nuclide transmutation method described above, apressure differential in the deuterium is provided between the onesurface side and the other surface side of the structure body in a statein which the material that undergoes nuclide transmutation is bound tothe one surface of the structure body that serves as the multilayerstructure, and a flux of deuterium from the one surface side to theother surface side in the structure body is produced, and thereby thenuclide transmutation reaction is produced with good repeatability forthe deuterium and the material that undergoes nuclide transmutation.

[0031] Furthermore, a nuclide transmutation method according to theeighth aspect of the present invention is characterized in thetransmutation material binding process including either a transmutationmaterial lamination process (step S04, step S44, or step S04 a in theembodiments) that laminates the material that undergoes nuclidetransmutation on the one surface of the structure body, or atransmutation material supply process (step S22 in the embodiments) thatexposes the one surface of the structure body to a gas or liquid thatincludes the material that undergoes nuclide transmutation.

[0032] According to the nuclide transmutation method described above, amaterial that undergoes nuclide transmutation is laminated on the onesurface of the structure body by a film formation process using atransmutation material lamination process such as electrodeposition,vaporization deposition, or sputtering, or the material that undergoesnuclide transmutation is mixed with a gas or liquid that includesdeuterium and the like, and thereby the material that undergoes thenuclide transmutation are disposed on the one surface of the structurebody.

[0033] Furthermore, a nuclide transmutation method according to a ninthaspect of the present invention is characterized in the transmutationmaterial binding process that binds the material that undergoes nuclidetransmutation to the one surface of the structure body.

[0034] According to the nuclide transmutation method described above,the material that undergoes nuclide transmutation is transmuted to anuclide having a similar isotopic ratio composition, and thereby thenuclide transmutation reaction can be promoted.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035]FIG. 1 is a drawing for explaining the principle of the nuclidetransmutation method according to the first embodiment of the presentinvention.

[0036]FIG. 2 is a cross-sectional structural drawing showing thestructure body used in the nuclide transmutation method according to thefirst embodiment of the present invention.

[0037]FIG. 3 is a structural diagram of the nuclide transmutation deviceaccording to the first embodiment of the present invention.

[0038]FIG. 4 is s cross-sectional structure drawing of the multilayerstructure body used in the nuclide transmutation device shown in FIG. 3.

[0039]FIG. 5A is a cross-sectional structural drawing of the mixedlayers and FIG. 5B is a cross-sectional structural drawing of thestructure body including the mixed layer.

[0040]FIG. 6 is a structural diagram of the device that adds a materialto be subjected to the nuclide transmutation to the multilayer structurebody.

[0041]FIG. 7 is a graph showing the spectra of Pr by XPS in on thesurface of the multilayer structure body shown in FIG. 4.

[0042]FIG. 8 is a graph showing the change in the number of Cs and Pratoms over time on the surface of the multilayer structure body shown inFIG. 5.

[0043]FIG. 9 is a graph showing the change in the number of atoms foreach of C, Mg, Si, and S over time on the surface of the multilayerstructure body in the third embodiment.

[0044]FIG. 10 is a graph showing the change in the number of atoms foreach of C, Mg, Si, and S over time on the surface of the multilayerstructure body in the fourth embodiment.

[0045]FIG. 11 is a cross-sectional structure showing a multilayerstructure body according to the second modified embodiment of thepresent invention.

[0046]FIG. 12 is a graph showing an XPS spectrum of Mo on the surface ofthe multilayer structure body shown in FIG. 11.

[0047]FIG. 13 is a graph showing the change in the number of Sr and Moatoms over time on the surface of the multiplayer structure body shownin FIG. 11.

[0048]FIG. 14 is a graph showing the change in the number of Sr and Moatoms over time on the multiplayer structure body shown in FIG. 11.

[0049]FIG. 15 is a graph showing the change of the isotopic ratio of thenatural Mo with the change of the atomic mass number over time.

[0050]FIG. 16 is a graph showing the change of the isotopic ratio of thenucleated Mo on the surface of the multilayer structure body accordingto the fifth embodiment of the present invention together with thechange in its atomic mass number.

[0051]FIG. 17. is a diagram showing the change of the isotopic ratio ofthe natural Sr, which is added as a material that undergoes nuclidetransmutation, together with the change in its mass number.

[0052]FIG. 18 is a diagram explaining the principle of the nuclidetransmutation according to the second embodiment of the presentinvention.

[0053]FIG. 19 shows a structure of the nuclide transmutation deviceaccording to the second embodiment of the present invention.

[0054]FIG. 20 is a drawing showing the surface on the electrolyte cellside of the multilayer structure body after experiments using thenuclide transmutation device shown in FIG. 19.

[0055]FIG. 21 is a graph showing the results of SIMS analysis of thesurface of the multilayer structure body after experiments using thenuclide transmutation device shown in FIG. 19.

[0056]FIG. 22 shows a structure of a nuclide transmutation deviceaccording the third embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0057] Below, the nuclide transmutation device and nuclidetransformation method according to the first embodiment of the presentinvention are explained referring to the figures.

[0058]FIG. 1 is a drawing for explaining the principle of the nuclidetransmutation method according to the first embodiment of the presentinvention; FIG. 2 is a cross-sectional structural drawing showing thestructure body 1 used in the nuclide transmutation method according tothe first embodiment of the present invention; FIG. 3 is a structuraldiagram of the nuclide transmutation device 30 according to the firstembodiment of the present invention; FIG. 4 is s cross-sectionalstructure drawing of the structure body 51 used in the nuclidetransmutation device shown in FIG. 3; FIG. 5A is a cross-sectionalstructural drawing of a mixed layer 22 and FIG. 5B is a cross-sectionaldrawing of the structure body 11 containing the mixed layer 22; FIG. 6is a diagram of the device that adds a material, that undergoes nuclidetransmutation, to the structure body 11.

[0059] As shown, for example, in FIG. 1, the device 10 that realizes thenuclide transmutation method according to the present embodimentcomprises a structure body 11 having a substantially plate shapecomprising palladium (Pd) or an alloy of Pd or another metal (forexample, Ti) that absorbs hydrogen, or an alloy thereof, and a materialthat undergoes nuclide transmutation attached to one surface 11A amongthe two the surfaces of this structure body 11; and in the device a flow15 of deuterium is generated in the structure body 11 due to the onesurface side 11A of the structure body 11 serving as a region 12 inwhich, for example, a load or the pressure of hydrogen due toelectrolysis is high and the other surface 11B side serving as a region13 in which the pressure of the deuterium due to vacuum exhaust and thelike is low; and the nuclide transmutation is carried out by thereaction between the deuterium and the material 14 that undergoesnuclide transmutation.

[0060] Here, as shown for example in FIG. 2, the structure body 11 ispreferably formed by a mixed layer 22 of a material that has arelatively low work function, that is, a material that emits electronseasily (for example, a material having a work function equal to or lessthan 3 eV), and Pd being formed on the surface of a Pd substrate 23, anda Pd layer 21 being laminated on surface of the mixed layer 22.

[0061] As shown in FIG. 3, the nuclide transmutation device 30 accordingto the present embodiment comprises an absorption chamber 31 having aninterior that can be maintained in an airtight state, a radiationchamber 34 provided inside this absorption chamber 31 that can bemaintained airtight due to the multilayer structure body 32, a deuteriumtank 35 that supplies deuterium into the absorption chamber 31 via thevariable leak pump 33, a radiation chamber vacuum gauge 36 that detectsthe degree of the vacuum in the radiation chamber 34, a substanceanalyzer 37 that detects the gaseous reaction products produced, forexample, from the multilayer structure body 32, and evaluates the amountof penetration of the deuterium that penetrates the multilayer structurebody 32 by measuring the amount of deuterium in the radiation chamber34, a turbo-molecular pump 38 that always maintains the interior of theradiation chamber 34 in a vacuum state, and a rotary pump 39 forpreliminary evacuating the radiation chamber 34 and the turbo-molecularpump 38.

[0062] Further, the nuclide transmutation device 30 comprises staticelectricity analyzer 40 that detects photoelectrons, ions, and the likeemitted from the atoms of the surface of the multilayer structure body32 that are excited due to irradiation by X-rays, an electron beam, anda particle beam and the like, an X-ray gun 41 for XPS (X-rayPhoto-electron Spectrometry) that radiates X-rays on one surface exposedto deuterium among the two surfaces of the multilayer structure body 32in the absorption chamber 31 that is exposed to deuterium, a pressuremeter 42 that detects pressure in the absorption chamber 31 into whichdeuterium has been introduced, an X-ray detector comprising, forexample, a high purity germanium detector 44 having a beryllium window43, an absorption chamber vacuum meter 45 that detects the degree of thevacuum in the absorption chamber 31, a vacuum valve that maintains theinterior of the absorption chamber 31 is a vacuum state 46 before theintroduction of the deuterium, for example, a turbo-molecular pump 47that evacuates the absorption chamber 31 to a vacuum state, and a rotarypump 48 for preliminary evacuating the absorption chamber 31 and theturbo-molecular pump 47.

[0063] In addition, by placing the absorption chamber 31 side of themultilayer structure body 32 in a condition in which the pressure of thedeuterium is relatively high placing the radiation chamber 34 side ofthe multilayer body 32 in a condition in which the pressure of thedeuterium is relatively low, and forming the pressure difference in thedeuterium on both surfaces of the multilayer structure body 32, a flowof deuterium from the absorption chamber 31 side to the radiationchamber 34 side is produced.

[0064] Here, as shown in FIG. 4, for example, the multilayer structurebody 32 is formed such that a mixed layer 22 of a material that has arelatively low work function (for example, a material having a workfunction equal to or less than 3 eV) and Pd is formed on the surface ofthe Pd substrate 32, the Pd layer 21 is laminated on the surface of thismixed layer 22, and a cesium (Cs) layer 5 is added to the surface of thePd layer 21 as the material that undergoes nuclide transmutation.

[0065] The nuclide transmutation device 30 according to the presentembodiment is provided, and next, the method for carrying out thenuclide transmutation using this nuclide transmutation device 30 will beexplained referring to the figures.

[0066] First, the Pd substrate 23 (for example, having a length of 25mm, a width of 25 mm, a depth of 0.1 mm, and a purity of 99.5% orgreater) shown in FIG. 2, for example, is degreased by ultrasoundcleaning over a predetermined time interval in acetone. In addition, ina vacuum (for example, equal to or less than 1.33×10⁻⁵ Pa), annealing,that is, heat processing, is carried out over a predetermined timeinterval at 900° C. (step S01).

[0067] Next, at room temperature, contaminants are removed from thesurface of the Pd substrate 23 after annealing by carrying out etchingprocessing over a predetermined time interval (for example, 100 seconds)using heavy aqua regia (step S02).

[0068] Next, using a sputtering method employing an argon ion beam, thestructure body 11 is produced by carrying out surface formation on thePd substrate 23 after the etching processing. Here, for example, thethickness of the Pd layer 21 shown in FIG. 2 is 400×10⁻¹⁰ m, and themixed layer 22 of the material having a low work function and the Pd, asshown in FIG. 5A, is formed by alternately laminating, for example, aCaO layer 57 having a thickness of 100×10⁻¹⁰ m and, or example, a Pdlayer 56 having a thickness of 100×10⁻¹, and thus the thickness of themixed layer 22 is 1000×10⁻¹⁰. In addition, by forming as a film a Pdlayer 21 on the surface of the mixed layer 22 of 400×10⁻¹⁰, thestructure body 11 is formed (step S03).

[0069] Next, by electrolysis of CsNO₃ of a dilute solution of D₂O (asolution of CsNO₃/D₂O), as an example that undergoes nuclidetransmutation, for example, the material Cs is added to the filmprocessed surface of the structure body 11. For example, like theelectrodeposition device 60 shown in FIG. 6 using 1 mM of a CsNO₃/D₂Osolution as the electrolyte 62, connecting the platinum electrode 63 tothe anode of the power source 61, connecting the structure body 11 tothe cathode, and carrying out electrolysis over a 10 second interval ata voltage of 1V, the reaction represented by the following chemicalFormula (1) is produced, a Cs layer 52 is added, and the multilayerstructure body 32 is formed (step S04).

Cs⁺+e⁻→Cs  (1)

[0070] In addition, the Cs layer 52 of the multilayer body 32 is facedtowards the absorption chamber 31 side, the absorption chamber 31 andthe desorption chamber 34 are closed into an airtight state byinterposing the multilayer structure body 32. The desorption chamber 34is evacuated first using a rotary pump 39 and a turbo molecular pump 38.Furthermore, the absorption chamber 31 is evacuated using the rotarypump 48 and the turbo molecular pump 47 by closing the variable leakvalve 33 and by opening the vacuum valve 46 (step S05).

[0071] Next, after sufficiently stabilizing the degree of the vacuum ofthe absorption chamber 31 (for example, to be equal to or less than1×10⁻¹⁵ Pa), the elements present on the surface of the multilayerstructure body 32 on the absorption chamber 31 side are analyzed by XPS(step S06). That is, the surface of the multilayer structure body 32 isirradiated by an X-ray beam from an X-ray gun 41, and energy of thephotoelectrons emitted from atoms on the surface of the multilayerstructure body 32 excited by the X-ray irradiation is analyzed by theelectrostatic analyzer 40 so that the elements present on the absorptionchamber 31 side surface of the multiplayer structure body 32 areidentified.

[0072] Next, after heating the multilayer structure body 32 by a heatingdevice (not shown), for example, to 70° C., the vacuum exhausting of theabsorption chamber 31 is suspended by closing the vacuum valve 46, adeuterium gas is introduced at a predetermined gas pressure into theabsorption chamber 31 by opening the variable leak valve 33, and theexperiment on nuclide transmutation is commenced. Here, the gas pressurewhen deuterium is introduced into the absorption chamber 31 is, forexample, 1.01325×10⁵ Pa (or 1 atmosphere).

[0073] In addition, measurement of the gaseous reaction product (forexample, the mass number A=1 to 140) is carried out using the massspectrograph 37 in the radiation chamber 34, and the diffusion behaviorof the deuterium that penetrates through the multilayer structure body32 and is radiated into the radiation chamber 34 is evaluated. Inaddition, measurement of the X-ray is carried out by a high puritygermanium detector 44 disposed on the absorption chamber 31 side of themultilayer structure body 32 (step S07).

[0074] Note that the amount of deuterium released into the desorptionchamber 34 after permeating through the multilayer structure body 32 iscalculated based on the degree of vacuum in the desorption chamber 34detected by a desorption chamber vacuum gauge 36 and a volume flow rateof a turbo molecular pump 38.

[0075] After the commencement of the introduction of the deuterium gasinto the absorption chamber 31, for example, after several tens ofhours, the temperature of the multilayer structure body 32 is restoredto room temperature. The introduction of the deuterium gas is suspendedby closing the variable leak valve 33, and furthermore, the absorptionchamber 31 is evacuated by opening the vacuum valve 46 and theexperiment on nuclide transmutation is ended.

[0076] In addition, after sufficiently stabilizing the degree of thevacuum in the absorption chamber 31 (for example, equal to or less than1×10⁻⁵ Ps), the elements present on the surface of the multilayerstructure body 32 on the absorption chamber 31 side is analyzed by XPS,and thereby the measurement of products is carried out (step S08).

[0077] In addition, the processing in the above-described steps S06 toS07 is repeated, and the change over time of the nuclide transmutationreaction is measured (step S09).

[0078] Additionally, the multilayer structure body 32 is extracted fromthe nuclide transmutation device 30, and the experiment on the nuclidetransmutation is ended (step

[0079] Below, the results of the two experiments on nuclidetransmutation carried out using the nuclide transmutation methodaccording to the present embodiment, that is, the example 1 and example2 when the identical experiment is carried out two times, will beexplained referring to FIG. 7 and FIG. 8.

[0080]FIG. 7 is a graph showing the spectrum of Pr using XPS in thesurface of the multilayer structure body 32 shown in FIG. 4, and FIG. 8is a graph showing the change over time in the number of atoms of Cs andPr in the surface of the multilayer structure body 32 shown in FIG. 4.

[0081] According to the results of the XPS analysis of the example oneand example two, in the example one and the example two the Cs (atomicnumber Z=55) of the multilayer structure body 32 decreases with thepassage of time, and for example, like the spectrum of Pr using XPSshown in FIG. 7, the Pr (praseodymium, atomic number Z=59) increased.

[0082] Below, the method of calculating the number of atoms of eachelement from the spectrum of Cs and Pr using XPS will be explained.

[0083] Moreover, the strength of X-rays radiated from the X-ray gun 41to the multilayer structure body 32 during the measurement by XPS ismade constant, and the region in which these X-rays are desorbed isassumed to be identical in each of the measurements of the example oneand the example two.

[0084] Furthermore, the region in which the X-rays are emitted on thesurface of the multilayer structure body 32 is, for example, a circularregion having a diameter of 5 mm, and from the estimation of the escapedepth of the photoelectrons that are emitted, the depth that can beanalyzed in XPS is, for example, 20×10⁻¹⁰.

[0085] In addition, the Pd that forms the Pd substrate 23 is an fcc(face-centered cubic) lattice, and thus the number of Pd atoms,calculated from the peak strength of the spectrum of PD obtained by XPS,is 3.0×10¹⁵.

[0086] In addition, the number of atoms of each element is calculated bycomparing the peak strength of the spectrum of each element obtained byXPS and the peak strength of the spectrum of Pd, referring to the ratioof the ionization cross section of each element, that is, the electronsin the inner shell of the elements, that are excited due to absorbingX-rays and the like. Moreover, in Table 1, the calculated value of theionization cross section of each element is shown as a relative value inthe case that the value of the 1s orbital of C (2.22×10⁻²⁴ m²) is set to‘1’. Further, in the following chart 1, 2p of Si, 2p of S, and 2p of C1are calculated as the sum of 2p_(3/2) and 2p_(1/2). TABLE 1 bondingenergy of ionization cross bonding energy inner shell electrons sectionof inner shell electrons ionization cross section C 1s (283.5 eV) 1.00Mg 2s (88.6 eV) 2.27 O 1s (543.1 eV) 2.29 Pd 3d_(5/2) (335.1 eV) 10.1 Si2p (99 eV) (*) 0.894 Pd 3d_(3/2) (340.4 eV) 7.03 Si 2s (149.8 eV) 0.884Cs 3d_(5/2) (726.6 eV) 22.93 S 2p (163 eV) (*) 1.85 Ce 3d_(5/2) (883.9eV) 28.57 Cl 2p (201 eV) (*) 2.47 Pr 3d_(5/2) (928.8 eV) 30.72

[0087] As shown in FIG. 8, in the first example, under initialconditions, 1.3×10¹⁴ atoms of Cs were reduced to 8×10¹³, and after 120hours, were reduced to 5×10¹³.

[0088] In contrast, although Pr was not present before the commencementof the experiment, after 48 hours, 3×10¹³ atoms thereof, were detected,and after 12 hours, the number was observed to increase to 7×10¹³ atoms.

[0089] Similarly, in the second example as well, with the passage oftime from the commencement of the experiment, a decrease in the numberof Cs atoms and Pr production and an increase in the number of Pr atomswas observed, showing a tendency substantially identical to that of thefirst example. Thus, this can be interpreted as showing that the nuclidetransmutation of Cs to Pr was occurring.

[0090] Moreover, in the following, we will consider whether or not thedetected Pr is due to contaminants.

[0091] In the first example and the second example of the presentembodiment as described above, analysis of elements was carried outwithout extracting the multilayer structure body 32 from the vacuumcontainer comprising the absorption chamber 31 and the radiation chamber34, and thus the causes of the introduction of contaminants that can beconsidered are contaminants included on the deuterium gas (D₂ gas) andcontaminants in the multilayer structure body 32.

[0092] In the case of analyzing D₂ gas in the nuclide transmutationdevice 30 when the D₂ gas is 99.6% pure, and the contaminant N₂ and D₂Oare equal to or less than 10 ppm, contaminants O₂, CO₂, and CO are equalto or less than 5 ppm, gases of contaminants other than thesecontaminants and hydrocarbons were not detected.

[0093] In contrast, in the multilayer structure body 32, the purity ofthe Pd was 99.5%, and the purities of CaO and CsNO₃ were 99.9%. Inaddition, as a result of carrying out quantitative analysis oflanthanides (₅₇La to ₇₁Lu) in the multilayer structure body 32 beforethe commencement of the experiment using glow desorption massspectrometry (GD-MS), Nd was detected at 0.02 ppm, and the otherlanthanides besides Nd were below detection limits, that is, equal to orless than 0.01 ppm.

[0094] Here, if we assume that 0.01 ppm of Pr, which is the detectionlimit, is present in the multilayer structure body 32 used in the firstexample and the second example (for example, 0.7 g≅7×10⁻³ mol), then thenumber of Pr atoms present in the multilayer structure body 32 would be4.2×10¹³.

[0095] In this case, based on the above assumption, if we assume thatthe Pr atoms detected in example 1 and example 2 are Pr atoms below thedetection limits, then it is also necessary to assume that all the Pratoms below the detection limit are disposed so as to be concentrated inthe region having a depth of several 10×10⁻¹⁰ m from the surface of themultilayer structure body 32, and a physical phenomenon in which the Pratoms scattered as contaminants in the multilayer structure body 32 areconcentrated only in proximity to the surface of the multilayerstructure body 32 is thermodynamically impossible. Thus, we cannotconclude that the Pr atoms detected in example one and example two arecontaminants included beforehand in the multilayer structure body 32.Furthermore, if they are impurities included beforehand in themultilayer structure body 32, we can determine that there is no timedependent change of the atomic number, that is, a change over time inthe number of atoms will maintain a constant value.

[0096] Based on the above, we can conclude that the Pr detected inexample one and example two is produced as a result of the nuclidetransmutation reaction.

[0097] Moreover, the experimental results of the above-described exampleone and example two are extremely well explained by the EINR model thatappeared in the journal Fusion Technology, published by the US AtomicEnergy Conference (Y. Iwamura, T. Itoh, N. Gotoh, and I. Toyoda,“Detection of Anomalous Elements, X-ray, and Excess Heat in a D₂-PdSystem and its Interpretation by the Electron-Induced Nuclear Reaction(EINR) Model”, Fusion Technology, vol. 33, no. 4, p. 476, 1998).

[0098] According to this EINR model, we can consider the Pr to beproduced from Cs according to the Formula (1) and Formula (2).

[0099] Moreover, in the following Formula (1) and Formula (2), d denotesdeuterium, e denotes electrons, ₂n denotes dineutrons, and ν denotesneutrinos. $\begin{matrix} {{\,_{1}^{2}d} + {\,_{- 1}^{0}e}}arrow{{\,_{0}^{2}n} + v}  & (2)\end{matrix}$

$\begin{matrix} {{{\,_{55}^{133}C}\quad s} + {4_{0}^{2}n}}arrow{{\,_{59}^{141}P}\quad r}  & (3)\end{matrix}$

[0100] As shown in Formula (2), according to the EINR model, deuteriumcaptures electrons to generate dineutrons, and simultaneously, nuclidetransmutation occurs due to reacting with substances such as Cs.Moreover, in Formula (3), the symbols for β decay, that is, the β⁻ decayfrom ¹⁴¹Cs (=¹³³Cs+4²n) to ¹⁴¹Pr, have been omitted.

[0101] As described above, according to the nuclide transmutation device10 of the present embodiment, a relatively large-scale device such as anuclear reactor or an accelerator are not necessary, and the process ofnuclide transmutation can be implemented with a relatively small-scaleconstruction.

[0102] In addition, according to the nuclide transmutation method of thepresent embodiment, the possibility that the number of atoms of Pr,which are not detected before the commencement of the experiment and aredetected to be increasing after the commencement of the nuclidetransmutation experiments, are detected due to contaminants includedbeforehand in the supplied D₂ gas or in the multilayer structure body 32is eliminated, and the production of a nuclide transmutation reactionfrom Cs to Pr can be repeated well and reliably.

[0103] Moreover, in the embodiment described above, the multilayerstructure body 32 was formed by adding a cesium (Cs) layer 52 to thesurface of the Pd layer 21 as a material that undergoes the nuclidetransmutation, but the invention is not limited thereby, and in place ofusing Cs as a material that undergoes the nuclide transmutation, othermaterials such as carbon (C) can be added.

[0104] Below, as a first modified example of the present embodiment, thecase of adding carbon (C), for example, as a material that undergoes thenuclide transmutation on the surface of the Pd surface 21, will beexplained referring to FIG. 9 and FIG. 10.

[0105]FIG. 9 is a graph showing the change in the number of atoms foreach of C, Mg, Si, and S over time on the surface of the multilayerstructure body 32 in the third example, and FIG. 10 is a graph showingthe change in the number of atoms for each of C, Mg, Si, and S over timeon the surface of the multilayer structure body 32 in the fourthexample.

[0106] In this first modified example, the point that differs greatlyfrom the first embodiment described above is the method of forming themultilayer structure body 32, and in particular, the process in step S04described above.

[0107] Specifically, after the step S03 described above, the multilayerstructure body 32 is formed by carbon (C) in the atmosphere adhering tothe surface of the Pd layer 21 due to exposing the structure body 11comprising the Pd substrate 23, mixed layer 22, and the Pd layer 21 tothe atmosphere (step S14).

[0108] In addition, the Pd layer 21 having the adhering C is facedtowards the absorption chamber 31, the absorption chamber 31 and theradiation chamber 34 are closed by interposing the multilayer structurebody 32 therebetween, and a vacuum desorption is respectively carriedout on both the absorption chamber 31 and the radiation chamber 34.

[0109] Then the processing in the following the above-described step S06is carried out.

[0110] Below, the results of two experiments, that is, the example threeand example four when the same experiment according to the firstmodified example is carried out two times, on nuclide transmutationexperiment carried out by the nuclide transmutation method of themodified example of the present embodiment is explained referring to thefigures.

[0111] In this case, by the results of the analysis of CPS in example 3and example 4, in example 3 and example 4, the C in the multilayerstructure body 32 decreases with the passage of time, and Si and S,which are reaction products, and Mg, which is an intermediate product,were detected.

[0112] In addition, similar to the embodiment described above, thenumber of atoms of each element is calculated from the spectrum of C,Mg, Si, and S by XPS.

[0113] As shown in FIG. 9, in example 3, the number of C atomsoriginating in hydrocarbons decreased 44 hours after the commencement ofthe experiment, while Mg, which was not present before the commencementof the experiment, was detected 44 hours later, and furthermore, hadsomewhat decreased after 116 hours.

[0114] Furthermore, Si and S, which were not present before commencementof the experiment, increased monotonically 44 hours later and 116 hourslater.

[0115] As shown in FIG. 10, in example 4, the number of C atomsoriginating in hydrocarbons decreased monotonically 24 hours, 76 hours,and 116 hours after the commencement of the experiment, while incontrast Mg, which was not present before the commencement of theexperiment, was produced 24 hours after commencement, and furthermore,monotonically decreased after 76 and 116 hours.

[0116] Furthermore, Si and S, which were not present before commencementof the experiment, monotonically increased 24, 76, and 116 hours aftercommencement.

[0117] According to the above results, the nuclide transmutation methodaccording to the modified example of the present invention resulted in Cbeing transmuted, and Mg, Si, and S being generated.

[0118] In this case, according to the EINR model described above, thenuclide transmutation of C is represented in Formula (2) described aboveand Formula (4). Moreover, in Formula 4, a reaction by a dineutroncluster (6²n, 2²n) is represented. $\begin{matrix}{{\,_{6}^{12}C}\overset{6_{0}^{2}n}{arrow}{{{\,_{12}^{24}M}\quad g}\overset{2_{0}^{2}n}{arrow}{{{\,_{14}^{28}S}\quad i}\overset{2_{0}^{2}n}{arrow}{\,_{16}^{32}S}}}} & (4)\end{matrix}$

[0119] Below, the second modified example of the present embodiment isexplained with reference to FIGS. 11 to 17 when, for example, strontium(Sr) is added on the surface of the Pd layer 21 as an element thatundergoes nuclide transmutation.

[0120]FIG. 11 is a cross-sectional structure diagram showing themultilayer structure body 32 related to the second modified example ofthe present embodiment. FIG. 12 is a graph showing the XPS spectrum ofthe Mo element on the surface of the multilayer structure body 32 shownin FIG. 11. FIGS. 13 and 14 show a time dependent change of atomicnumbers of respective Sr and Mo elements on the surface of themultilayer structure body 32. FIG. 15 shows the change of a isotopicratio and the atomic mass number of natural Mo. FIG. 16 shows the changeof an isotopic ratio and the atomic number of Mo observed on themultilayer structure body 32 in the fifth embodiment. FIG. 17 is a graphshowing the change of the isotopic ratio and the atomic mass number ofthe natural Sr added as a material that undergoes nuclide transmutation.

[0121] In this second modified example, the Sr layer 53 is added on themultilayer structure body 32 in place of the Cs layer 52 used for beingsubjected to the nuclide transmutation. That is, the point of the secondmodified example which differs from the above-described first modifiedexample is the method of forming the multilayer structure body 32,particularly, the processing in step S04. Note that, in the secondmodified example, the platinum substrate 23 has a size of 25 mm×25mm×0.1 mm (length×width×thickness) and having a impurity of more than99.9%.

[0122] In the second modified example, after the above-described stepS03, Sr, for example, is added as the material that undergoes nuclidetransmutation on the film formed surface of the structure body byelectrolysis of a diluted solution of SrO in D₂O (Sr(OD)₂/D₂O solution)on the film forming surface of the multiplayer structure body 11. In theelectrodeposition device 60, for example, shown in FIG. 6, 1 mM of theSr(OD)₂/D₂O solution is used, and electrolysis is carried out, forexample, for 10 seconds at 1V after connecting the anode of the powersource 61 to the platinum anode 63 and connecting the cathode of thepower source 61 to the multilayer structure body 11. The chemicalreaction shown by the formula (5) takes place by the electrolysis, andthe Sr layer 53 is deposited on the surface of the multilayer structurebody 32 (step S04 a)

Sr²⁺+2e⁻→Sr  (5)

[0123] Subsequently, the Sr layer 53 of the multilayer structure body 53is directed to the absorption chamber 31 and the processes below stepS05 are conducted.

[0124] Hereinafter, two results of the nuclide transmutationexperiments, that is, the results of the example 5 and example 6, whichwere conducted by repeating the same experiment for two times in linewith the nuclide transmutation method according to the second modifiedexample of the present embodiment are described.

[0125] The analysis of XPS obtained in the example 5 and example 6indicated that Sr (the atomic number Z=38) on the multilayer structurebody 32 has been decreased with the passage of time, and Mo (molybdenum,Z=42) has been increased as shown by the Mo spectrum of XPS in FIG. 12.

[0126] The calculation of the number of atoms of Sr and Mo from the XPSspectrum of Sr and Mo are conducted by the same method as that in thefirst embodiment.

[0127] That is, it is assumed that the intensity of the X-ray irradiatedon the multilayer structure body 32 from the X-ray gun during XPsmeasurement is constant and that the regions irradiated by X-ray for themeasurements in example 5 and example 6 are the same.

[0128] Furthermore, it is also assumed that the region on the multilayerstructure body 32 irradiated by X-rays is, for example, a circle with adiameter of 5 mm and that the measurable surface thickness by XPS is20×10⁻¹⁰ m from the estimation of the depth of the photoelectronsescaped from the surface.

[0129] The number of atoms of Pd is assumed to be 3×10¹⁵ based on thepeak intensity of the Pd spectrum obtained by XPS, assuming that the Pdconstituting the Pd substrate is composed of a face centered cubic (fcc)crystal.

[0130] The number of atoms of each elements is calculated by comparisonof the peak intensity of each element with the peak intensity of the Pdspectrum obtained by XPS, with reference to the ionization cross sectionof each element, that is, the ratio of inner-shell electrons excited byabsorbing X-rays.

[0131] As shown in FIG. 13, it has been observed that, in example 5, thenumber of atoms of 1.2×10¹⁴ of Sr present at the initial condition isreduced to 1.0×10¹⁴ after 80 hours, and further reduced to 8×10¹³ after400 hours.

[0132] In contrast, it was observed that 2.2×10¹³ atoms of Mo, whichwere not present before starting the experiment, were observed after 80hours, and the number of atoms of Mo was increased to 3.2×10¹³ after 240hours, and was further increased to 3.8×10¹³ after 400 hours.

[0133] Similarly, in experiment 6 shown in FIG. 14, the same tendency asthe case of example 5 was observed. That is, the number of Sr atoms isreduced with the passage of time, and generation and an increase ofnumber of Mo atoms, which is not present at the initial condition, areobserved.

[0134] Furthermore, in both examples 5 and 6, since the time dependentreduction number of Sr atoms approximately conforms with the timedependent increasing number of Mo atoms, this tendency is interpreted tomean that the nuclide transmutation occurs from Sr to Mo. Consequently,it is possible to mention that the experiments in both examples 5 and 6yield reproducible results.

[0135] In addition, in example 5, the isotopic ratio of Mo generated bythe experiment is calculated through an analysis of the surface of themultilayer structure body 32 using SIMS (Secondary Ion MassSpectroscopy) after the above-described step S10.

[0136] As shown in FIG. 6, the isotopic ratio of Mo observed in example5 when compared to that of the isotopic ratio of the natural Moindicates that a particular isotope of Mo, that is, ⁹⁶Mo, shows adramatically high abundance ratio.

[0137] As shown in FIG. 17, the isotopic ratio of the natural Sr addedto the multilayer structure body 32 indicated that a particular isotopeof Sr, that is, ⁸⁸Sr, shows a remarkably high abundance ratio. The aboveresults clearly indicate that there is a strong correlation between theisotopic ratio of a nuclide (Sr) that undergoes nuclide transmutationand the isotopic ratio of the material (Mo) observed after theexperiment, so that it can be concluded that the Mo detected in examples5 and 6 is generated by the nuclide transmutation of Sr.

[0138] Furthermore, the experimental results of examples 5 and 6 arequite well explainable by the above-mentioned EINR model, and it ispossible to explain that ⁹⁶Mo is formed by the reaction shown inequations (2) and (6), which is described later.

[0139] Note that the letter symbol of β⁻ decay, that is, the decay of⁹⁶Sr (=⁸⁸Sr+4²n) towards ⁹⁶Mo, is omitted. $\begin{matrix} {{{\,_{38}^{88}S}\quad r} + {4_{0}^{2}n}}arrow{{\,_{42}^{96}M}\quad o}  & (6)\end{matrix}$

[0140] Below, the nuclide transmutation device and nuclide transmutationmethod according to the second embodiment of the present invention willbe explained referring to the figures.

[0141]FIG. 18 is a drawing for explaining the principle of the nuclidetransmutation method according to the second embodiment of the presentinvention. FIG. 19 is a structural diagram of the nuclide transmutationdevice according to the second embodiment of the present invention.

[0142] As shown, for example, in FIG. 18, the device 70 for realizingthe nuclide transmutation method according to the present embodimentcomprises an anode 71 of platinum and the like, a cathode 72 comprisingpalladium (Pd) or a Pd alloy, or another metal that can absorb hydrogen(for example, Ti and the like), or an alloy thereof, a heavy watersolution 73 into which the cathode 71 and one surface of the cathode 72are immersed, an electrolyte cell 74 made fluid-tight by the cathode 72and filled with the heavy water solution that includes material thatundergoes the nuclide transmutation, and a vacuum container 75 sealedair-tight by the anode 72, and wherein a flow of deuterium is generatedin the cathode 72 by one surface 72A side of the cathode 72 being made aregion having a high deuterium pressure due to electrolysis and thelike, and the other surface 72B side being made a region having a lowdeuterium pressure due to vacuum evacuation and the like, and thenuclide transmutation is carried out by a reaction between the deuteriumand the material that undergoes nuclide transmutation.

[0143] Here, the cathode 72 has a structure identical, for example, tothe structure body II shown in FIG. 2, and preferably, a mixed layer 22of a material having a relatively low work function, that is, a materialthat emits electrons easily (for example, a substance having a workfunction less than 3 eV), and Pd is formed on the surface of the Pdsubstrate 23, and the Pd layer 21 is formed by lamination on the surfaceof this mixed layer 22.

[0144] As shown in FIG. 19, the nuclide transmutation device 80according to the present embodiment comprises a power source 81, anelectrolytic cell 83 providing a voltmeter 82, an electrolytic solution84 stored in the electrolyte cell 83, a vacuum container 85, a spiralrefrigerating tube 86 made, for example, of an insulating resin thatfreezes the electrolytic solution 84 in the electrolyte cell 86, acatalyst 87, an anode electrode 88 of platinum and the like that isconnected to the anode of the power source 81 and is immersed in theelectrolytic solution 84, a multilayer structure body 89 that maintainsthe electrolyte cell 83 in a liquid-tight condition and at the same timemaintains the vacuum container 85 in an air-tight state and is connectedto the cathode of the power source 81, a thermostat 90 that accommodatesthe electrolyte cell 83 and the vacuum container 85 and controls thetemperature, and a vacuum exhaust pump 91 that places the vacuumcontainer 85 in a vacuum state.

[0145] Here, the electrolyte cell 83 made, for example, of an insulatingresin and the vacuum container 85 made, for example, of stainless steel,are sealed in liquid-tight and air-tight states by the multilayerstructure body 89 via, for example, a Culret's O-ring, and so to speak,connected via the multilayer structure body 89.

[0146] In addition, the electrolyte solution 84 stored in theelectrolyte cell 83 is a heavy water solution that includes, forexample, cesium (Cs) as a material that undergoes nuclide transmutation.This electrolyte solution 84 may be a Cs₂(SO₄) heavy water solutionhaving a concentration, for example, of 3.1 mol/L.

[0147] Moreover, the catalyst 87 is formed by electrodepositing platinumblack on platinum, water is produced from most of the hydrogen andoxygen generated by the electrolysis of the electrolytic solution 84,and this is returned to the electrolyte solution 84.

[0148] The nuclide transmutation device according to the presentembodiment provides the structure described above, and next the methodof carrying out nuclide transmutation using this nuclide transmutationdevice 80 will be explained referring to the figures.

[0149] First, the structure body 11 is produced in a manner identical tothe step S01 to step S03 in the nuclide transmutation method in theabove-described first embodiment.

[0150] In addition, this structure body 11 serves as the multilayerstructure body 89, the Pd layer 12 of the multilayer structure body 89is faced towards the electrolytic cell 83 side, and the electrolyticcell 83 and the vacuum container 85 are sealed in respectivelyliquid-tight and air-tight states (step S21).

[0151] Next, a Cs₂(SO₄) heavy water solution having a concentration, forexample, of 3.1 mol/L is injected as an electrolytic solution 84 in theelectrolytic cell 83. Furthermore, the space in the electrolytic cell 83not filled by the electrolytic solution 84 is filled with nitrogen gasand sealed, and the pressure in the electrolytic cell 83 is maintainedat, for example, 1.5 kg/cm² (step S22).

[0152] In addition, the vacuum container 85 is evacuated by a vacuumpump 91, and maintained in a vacuum state (step S23).

[0153] Additionally, a refrigerant is supplied to a refrigerant pipe 86made of an insulating resin and the like, and the temperature in theelectrolytic cell 83 is maintained at a predetermined constanttemperature (step S24).

[0154] In addition, an anode electrode 88 made, for example, ofplatinum, and the multilayer structure body 89 serving as the cathode,which are immersed in the electrolytic solution 84 in the electrolyticcell 83, are connected to the power source 81, and the electrolyticreaction is generated by the power supplied from the power source 81(step S25).

[0155] Here, the current supplied during the electrolysis is graduallyraised from 1A to 2A over a three hour interval, and subsequentlymaintained at 2A.

[0156] In addition, after commencement of the electrolysis, thetemperature of the thermostat 90 is set to 70° C. after 12 hours, andthe temperature is thereafter maintained at this temperature (step S26).

[0157] This electrolysis is suspended after a predetermined timeinterval, for example, 7 days, and the temperature of the thermostat 90is set to room temperature (step S27).

[0158] In addition, the multilayer structure body 89 is extracted fromthe nuclide transmutation device 80, and the surface of the multilayerstructure body 89 is analyzed by secondary ion mass spectroscopy (SIMS)(step S28).

[0159] Below, the results of experiments using the nuclide transmutationexperiment carried out using the nuclide transmutation method accordingto the present embodiment described above, that is, example seven, areexplained referring to FIG. 20 and FIG. 21.

[0160]FIG. 20 is a drawing showing the surface on the electrolyte cellside of the multilayer structure body after experiments using thenuclide transmutation device shown in FIG. 19, and FIG. 21 is a graphshowing the results of the SIMS analysis of the surface of themultilayer structure body after experiments using the nuclidetransmutation device shown in FIG. 19.

[0161] With respect to the part 96 shown in FIG. 20 that the deuteriumpenetrates and the part 95 shown in FIG. 20 that the deuterium does notpenetrate, as shown in FIG. 21, for ¹⁴⁰Ce the intensity of secondaryions agree, but for ¹³⁹La and ¹⁴¹Pr, the part not penetrated by thedeuterium, that is, the part in which the nuclide transmutation reactionwas produced, the intensity of the secondary ions became large.

[0162] In addition, although it is not possible to distinguish whetherthe mass number A=142 is ¹⁴²Ce or ¹⁴²Nd, the intensity of the secondaryions became large in the part 96 that the deuterium penetrated.

[0163] Thereby, it can be concluded that at least ¹⁴¹Pr is a substanceformed by the nuclide transmutation of Cs.

[0164] As described above, according to the nuclide transmutation device80 of the present embodiment, a relatively large-scale device such as anuclear reactor or accelerator are unnecessary, and the nuclidetransmutation process can be carried out with a relatively small-scalestructure.

[0165] Furthermore, while the structure differs from the nuclidetransmutation device 30 according to the first embodiment describedabove, experimental results were obtained showing that the nuclidetransformation reaction from Cs to Pr is produced, and the effectivenessof the essential means of the present invention can be shown.

[0166] In addition, according to the nuclide transmutation method of thepresent embodiment, in the multilayer structure body 89, from acomparison of the part 96 that the deuterium penetrated and the part 95that the deuterium did not penetrate, it can be reliably shown that atleast a nuclide transmutation reaction from Cs to Pr is produced.

[0167] Moreover, in the present embodiment, a heavy water solution thatincludes a material that undergoes the nuclide transmutation was used asthe electrolyte solution 84, but the invention is not limited thereby,and on one surface of the multilayer structure body 89, a substance thatundergoes nuclide transmutation, for example Cs can be laminated by afilm formation process such as vacuum deposition or sputtering, and thesurface on which this Cs is laminated is faced towards the electrolyticcell 83, and immersed in an electrolytic solution 84 comprising theheavy water solution stored in the electrolytic cell 83. In this case,including a substance, for example, Cs, that undergoes nuclidetransmutation in the heavy water solution is not necessary.

[0168] Moreover, in the present embodiment described above, the heavywater solution that includes Cs as the electrolyte solution 84 is used,but the invention is not limited thereby, and instead of Cs, anothermaterial such as sodium (Na) can be added as the material that undergoesthe nuclide transformation.

[0169] Below, as a modified example of the present embodiment, the casein which sodium (Na) is added to the heavy water solution as thematerial that undergoes the nuclide transmutation will be explained.

[0170] In this modified example, the major point of difference with thesecond embodiment described above is the processing from step S22 andsubsequent steps, as described above.

[0171] Specifically, after the above-described step S21, only, forexample, 400 ppm of sodium is added as the electrolyte solution 84 inthe electrolyte cell 83, and LiOD heavy water solution having aconcentration of 4.3 mol/L is injected.

[0172] Furthermore, the contents of the space not filled by theelectrolyte solution 84 in the electrolyte cell 83 is filled withnitrogen gas and sealed, and the pressure in the electrolyte cell 83 ismaintained at, for example, 1.5 kg/cm² (step S32).

[0173] In addition, the inside of the vacuum container 85 is evacuatedby the vacuum pump 91, and is maintained in a vacuum state (step S33).

[0174] Additionally, a refrigerant is supplied into the refrigerationtube 86 made, for example, from an insulating resin, and the temperaturein the electrolyte cell 83 is maintained at a predetermined constanttemperature (step S34).

[0175] In addition, the anode electrode 88 that is made from platinumand the like and immersed in the electrolyte solution 84 in theelectrolyte cell 83 and the multilayer structure body 89 serving as acathode are connected to the power source 81, and an electrolyticreaction is produced due to the power supplied from the power source 81(step S35).

[0176] Here, the current supplied during electrolysis is graduallyraised over, for example, a six hour interval from 0.5 A to 2 A, andsubsequently maintained at 2A.

[0177] In addition, this electrolysis is suspended after a predeterminedinterval, for example, after continuing for 7 days, and the temperatureof the thermostat 90 is set to room temperature (step S36).

[0178] Additionally, the multilayer structure body 89 is extracted fromthe nuclide transmutation device 80, and the surface of the multilayerstructure body 89 is analyzed using electron probe microanalysis (EPMA)(step S37).

[0179] Below, the experimental results of three nuclide transmutationexperiments carried out using the nuclide transmutation method accordingto the modified examples of the second embodiment of the presentinvention described above, that is, example 8, example 9, and example10, which are the same experiment carried out three times.

[0180] Moreover, in the following Table 2, for example 8, example 9, andexample 10, the results of the analysis of the electrolyte solution 84using inductive coupled plasma—Auger electron spectrometry (ICP-AES) areshown. Moreover, the results of analysis of the electrolyte solution 84before the commencement of the experiments are shown as comparativeexamples. TABLE 2 Comparison Example Example example Example six seveneight Na 430 25 16 56 (ppm) 0.086 0.005 0.003 0.011 (g) 2.3 × 10²¹ 1.3 ×10²⁰ 8.4 × 10¹⁹ 2.9 × 10²⁰ (Atoms) Al <1 410 420 310 (ppm) <2 × 10⁻⁴0.082 0.084 0.062 (g) <2 × 10¹⁸ 1.8 × 10²¹ 1.9 × 10²¹ 1.4 × 10²¹ (Atoms)

[0181] As shown in Table 2, in the electrolyte solution 84 before thecommencement of the experiments, the Na was at 430 ppm, and Al was equalto or less than the detection limit of 1 ppm.

[0182] In contrast, after the nuclide transmutation experiment, the Nabecame several tens of ppm, a value being one order lower, and the Alhad become several tens of a ppm. The change in the electrolyte solution84 after the commencement of the experiment carried out onlyelectrolysis by providing current from the power source 81, and othermaterials were not introduced from the outside.

[0183] In addition, regarding the number of atoms (Atom, in Table 2), itcould be confirmed that the decreased number of Na atoms fell from2.2×10²¹ to about 2.0×10²¹, and the increased amount of the Alsubstantially agreed with this.

[0184] This result is represented by the above Formula (2) and thefollowing Formula (7) in the EINR model described above. $\begin{matrix} {{\,_{11}^{23}{Na}} + {2_{0}^{2}n}}arrow{{\,_{11}^{27}{Na}}\overset{\beta -}{arrow}{{{\,_{12}^{27}M}\quad g}\overset{\beta -}{arrow}{\,_{13}^{27}{Al}}}}  & (7)\end{matrix}$

[0185] Here, for Na, the natural abundance of ²³Na is 100%, and for Al,the natural abundance of ²⁷Al is 100%. It can be inductively determinedfrom past experimental data that nuclide transmutation is easilyproduced between nuclides having similar isotopic ratio compositions,and it can be inferred that the possibility that Na transmutes to Al ishigh since the isotopes that exists stably for both elements Na and Alare unique.

[0186] In addition, as a result of analysis of the multilayer structurebody 89 using EPMA, Al was detected from the central part of themultilayer structure body 89, that is the part that the deuteriumpenetrated. Because Al is an amphoteric metal, it can be electrolyzed inthe electrolytic solution 84, but by detecting Al from the center partof the surface of the multilayer structure body 89, we can conclude thatAl was produced by the nuclide transmutation of Na.

[0187] Moreover, in the present embodiment, a heavy water electrolytesolution that includes a material that undergoes the nuclidetransmutation is used, but the invention is not limited thereby, and onone of the surfaces of the multilayer structure body 89, a material thatundergoes nuclide transmutation, for example, Na, can be laminated usinga film formation method such as vacuum deposition or sputtering, thesurface on which this Na has been laminated can be faced towards theinside of the electrolytic cell 83, and this can be immersed in theelectrolytic solution 84 comprising the heavy water solution stored inthe electrolyte cell 83. In this case, it is not necessary to include amaterial that undergoes the nuclide transmutation in the heavy watersolution, that is, Na.

[0188] Below, the nuclide transmutation device and the nuclidetransmutation method according to the third embodiment of the presentinvention are explained with reference to the attached drawings.

[0189]FIG. 22 shows a structure of the nuclide transmutation device 100according to the third embodiment of the present invention.

[0190] The nuclide transmutation device 100 according to this embodimentcomprises a desorption chamber 101 having an interior that can bemaintained in an airtight state, an absorption chamber 103, disposedinside of the desorption chamber 101 and having an interior that can bemaintained in an airtight state through a multilayer structure body 102,a deuterium tank 106 for supplying deuterium into the absorption chamber103 through a regulator valve 104 and a valve 105, a pressure meter 107for detecting the inside pressure of the absorption chamber 103, aconnecting pipe 109 for connecting the desorption chamber 101 and aabsorption chamber 103 through a vacuum valve 108, a turbo-molecularpump 110 for maintaining the inside of the desorption chamber 101, arotary pump for preliminary evacuation of the desorption chamber 101,the absorption chamber 103, and the turbo-molecular pump 110, and avacuum gauge 112 for detecting the degree of vacuum in the desorptionchamber 101.

[0191] The nuclide transmutation method using the above-describednuclide transmutation device 100 according to this embodiment will bedescribed below with reference to the attached drawings.

[0192] First, a platinum substrate 23 (for example, having a size of 70mm in diameter and 0.1 mm in thickness and a purity of more than 99.9%)shown in, for example, FIG. 2, is degreased by ultrasonic cleaning inacetone over a predetermined time. Then, the substrate is heat treated,that is, annealed at a temperature of, for example, 900° C., in an argonatmosphere (step S42).

[0193] Subsequently, the platinum substrate 32, after the annealingprocess, is subjected to etching, for example, using a 1.5 times dilutedaqua regia at room temperature for a predetermined time (for example,100 seconds) to remove impurities on the substrate surface (step S42).

[0194] Next, similarly to the above-described step S03, a multilayerstructure body is formed by depositing films on the platinum substrate23 after the etching process by a sputtering method using an argon beam.

[0195] Furthermore, a multilayer structure body 102 is formed byaddition of a Cs layer that undergoes nuclide transmutation on the filmdeposited surface of the multilayer structure body 11 by electrolysis ofthe D₂O diluted solution of CsNO₃ (CsNO₃/D₂O solution) (step S44).

[0196] The desorption chamber 103 and the absorption chamber 101 isclosed so as to be airtight after the Cs layer of the multilayerstructure body 102 is directed towards the absorption chamber 103. Then,the valve 105 is closed, the vacuum valve 108 in the connecting pipe 109is opened, and the desorption chamber 101 and the absorption chamber 103are evacuated using the rotary pump 111 and the turbo-molecular pump 110(step S45).

[0197] Subsequently, after the multilayer structure body 102 is heatedto, for example, 70° C. by a heating device (not shown), the vacuumvalve 108 is closed and evacuation of the absorption chamber 103 isstopped. Then, deuterium gas is introduced into the absorption chamber103 at a predetermined pressure and the experiment of the nuclidetransmutation is commenced. The predetermined pressure at the time ofintroducing the deuterium gas is regulated by the regulator valve 104,and the pressure is determined, for example, to be 1.01325×10⁵ (1 atm)(step S46).

[0198] The amount of the deuterium gas discharged in the desorptionchamber 101 is calculated based on the degree of vacuum detected by, forexample, the vacuum gauge 112 and the flow rate of the turbo-molecularpump 110.

[0199] After several tens of hours after starting introduction of thedeuterium gas in the absorption chamber 103, the temperature of themultilayer structure body 102 is returned to room temperature. The valve105 is closed and after stopping the introduction of the deuterium gasinto the absorption chamber 103, the absorption chamber 103 is evacuatedand the nuclide transmutation experiment is completed (step S47).

[0200] The multilayer structure body 102 is taken out from the nuclidetransmutation chamber 100 and the multilayer structure body 102 isetched by aqua regia for preparing a solution which contains theelements present on the surface of the multilayer structure body 102.This solution is analyzed by a ICP-MS (Inductive Coupled Plasma—Massspectrometry) for quantitative analysis of the elements present on thesurface of the multilayer structure body 102 (step S48).

[0201] Below, the results of two repeated experiments by the samemethod, that is, the experiments 11 and 12, based on the same nuclidetransmutation method according to the above-described embodiment of thepresent invention are described.

[0202] In the following Table 3, the results of the ICP-MS analyses fortwo samples obtained in the examples 11 and 12 are described. TABLE 3 PrCs Example 11  1.3 μg 2.3 μg Comparative Example 0.008 μg 3.8 μg Example12  0.12 μg —

[0203] As shown in Table 3, it was found that the contents of Pr and Cswere 0.008 μg and 3.8 μg, respectively, in the solution of thecomparative example, which is obtained from the multilayer structurebody 102 before starting the experiments

[0204] In contrast, after the experiments of the nuclide transmutation,the content of Pr is increased to 1.3 μg, which is more than 100 timesgreater than the initial weight, and the content of Cs is decreased to2.3 μg.

[0205] In the experiment 12, the content of Pr increases to 0.12 μg,which corresponds to a weight more than ten times greater than theinitial weight.

[0206] Consequently, it is concluded that the above results indicatethat the increase of Pr observed in examples 11 and 12 is caused by thenuclide transmutation from Cs to Pr.

[0207] As described above, although the nuclide transmutation device 100according to the present invention has a relatively small-scalestructure, it is confirmed that the present nuclide transmutation deviceis able to carry out nuclide transmutation instead of using large saclesystems such as a nuclear reactor or a particle accelerator.

[0208] In addition, in spite of the fact that the present nuclidetransmutation device and the multilayer structure body differ from thenuclide transmutation device 30 and the multilayer structure bodyaccording to the first embodiment, both of the nuclide transmutationdevices and multilayer structure bodies are confirmed to be able tocarry out the nuclide transmutation such as from Cs to Pr successfully,which results in showing the substantial effectiveness of the presentinvention.

[0209] In addition, in the first embodiment, the second embodiment, andthe third embodiment of the present invention described above, palladium(Pd) was used as the metal for absorbing the hydrogen, but the inventionis not limited thereby, and a Pd alloy, or, for example, another metalthat absorbs hydrogen, such as Ti, Ni, V, or Cu, or an alloy thereof canbe used.

[0210] As explained above, according to the first aspect of the nuclidetransmutation device of the present invention, nuclide transmutation canbe carried out with a relatively small-scale device compared to thelarge-scale devices such as accelerators and nuclear reactors, apressure differential in the deuterium between the one surface and theother surface of the structure body is provided, and within thestructure body a flux of deuterium from one surface side to the othersurface side is produced, and thereby an easily reproducible nuclidetransmutation reaction can be produced for the deuterium and thematerial that undergoes nuclide transmutation.

[0211] Furthermore, according to the second aspect of the nuclidetransmutation device of the present invention, the absorption part ispressurized by the deuterium supply device, and at the same time, thepressure in the radiation part is reduced to a vacuum state by theexhaust means, and thus a pressure differential in the deuterium isformed in the structure body.

[0212] Furthermore, according to the third aspect of the nuclidetransmutation device of the present invention, by electrolyzing theelectrolytic solution on one surface of the structure body with thestructure body serving as a cathode, deuterium is absorbed effectivelyinto the structure body due to the high pressure, and by reducing thepressure of the radiation part to a vacuum state using the exhaustdevice, a pressure differential in the deuterium is formed in thestructure body.

[0213] Furthermore, according to the fourth aspect of the nuclidetransmutation device of the present invention, the transmutationmaterial lamination device can laminate the material that undergoes thenuclear transmutation on one surface of the structure body by a surfaceforming process, such as electrodeposition, vapor deposition, orsputtering.

[0214] Furthermore, according to the fifth aspect of the nuclidetransmutation device of the present invention, the material thatundergoes nuclide transmutation can be bound to one surface of thestructure body by mixing the material that undergoes nuclidetransmutation in, for example, a gas or liquid that includes deuterium.

[0215] Furthermore, according to the sixth aspect of the nuclidetransmutation device of the present invention, a mixed layer thatincludes a material having a low work function is provided on thestructure body that serves as the multilayer structure, and thereby therepeatability of the production of the nuclide transmutation reaction isimproved.

[0216] Moreover, according to the first through sixth aspects of thenuclide transmutation device of the present invention, the production ofthe nuclide transmutation reaction can be further promoted bytransmuting the material that undergoes nuclide transmutation to anuclide having a similar isotope ratio composition, and therepeatability of the generation of the nuclide transmutation reactioncan be improved.

[0217] In addition, according to the seventh aspect of the nuclidetransmutation device of the present invention, a flux of deuterium fromthe one surface side to the other surface side within the structure bodyis produced, and thereby the nuclide transmutation reaction is producedwith good repeatability for the deuterium and the material thatundergoes nuclide transmutation.

[0218] Furthermore, according to the eighth aspect of the nuclidetransmutation method of the present invention, a material that undergoesnuclide transmutation is laminated on the one surface of the structurebody by a film formation process using a transmutation materiallamination process such as electrodeposition, vaporization deposition,or sputtering, or the material that undergoes nuclide transmutation ismixed with a gas or liquid that includes deuterium and the like, andthereby the material that undergoes the nuclide reaction is bound to theone surface of the structure body.

[0219] Furthermore, according to the ninth aspect of the nuclidetransmutation method of the present invention, the material thatundergoes nuclide transmutation is transmuted to a nuclide having asimilar isotopic ratio composition, and thereby the nuclidetransmutation reaction can be promoted, and the repeatability of thegeneration of the nuclide transmutation reaction can be improved

What is claimed is:
 1. A nuclide transmutation device comprising: astructure body that is made of palladium or a palladium alloy, or ahydrogen absorbing metal other than palladium, or a hydrogen absorbingalloy other than a palladium alloy; an absorption part and a desorptionpart that are disposed so as to surround said structure body on thesides and form a closed space that can be sealed by said structure body;a high pressurization device that produces a relatively high pressure ofdeuterium at said absorption part on the side of the surface of saidstructure body; a low pressurization device that produces a relativelylow pressure of deuterium at said desorption part side on the other sideof the surface of said structure body; and a transmutation materialbinding device that binds the material that undergoes nuclidetransmutation onto one surface of said structure body.
 2. A nuclidetransmutation device according to claim 1, wherein said highpressurization device comprises an deuterium supply device for supplyinga deuterium gas to said absorbing part; and said low pressurizationdevice comprises an exhaust device which evacuates said desorption part.3. A nuclide transmutation device according to claim 1, wherein saidhigh pressurization device comprises an electrolysis device that carriesout electrolysis of said electrolytic solution using said structure bodyas a cathode by supplying sais electrolytic solution containingdeuterium to said absorption part; and said lower pressurization devicecomprises an exhaust device that evacuates said desorption part.
 4. Anuclide transmutation device according to claim 1, wherein saidtransmutation material binding device comprises a transmutation materiallamination device that laminates said material that undergoes nuclidetransmutation onto one surface of said structure body.
 5. A nuclidetransmutation device according to claim 1, wherein said transmutationmaterial binding device provides a transmutation material supply devicethat supplies said material that undergoes nuclide transmutation to saidabsorption part, and exposes one surface of said structure body to a gasor liquid that includes said material that undergoes the nuclidetransmutation.
 6. A nuclide transmutation device according to claim 1,wherein said structure body provides from one surface to the othersurface in order: a base material that is made of palladium or apalladium alloy, or a hydrogen absorbing metal other than palladium, ora hydrogen absorbing alloy other than a palladium alloy; a mixed layerthat is formed on the surface of said base material and comprisespalladium or a palladium alloy, or a hydrogen absorbing metal other thanpalladium or a hydrogen absorbing alloy other than a palladium alloy,and a material having a low work function (CaO in the embodiments); anda surface layer that is formed on the surface of said mixed layer andcomprises palladium or a palladium alloy, or a hydrogen absorbing metalother than palladium or a hydrogen absorbing alloy other than apalladium alloy.
 7. A nuclide transmutation method comprising processingsteps of the structure body comprising palladium or a palladium alloy,or a hydrogen absorbing metal other than palladium, or a hydrogenabsorbing alloy other than a palladium alloy, the method comprises thesteps of: a high pressurizing process that brings about a state in whichthe pressure of the deuterium is relatively high on one surface side ofsaid structure body; a low pressurizing process that brings about astate in which the pressure of the deuterium is relatively low on theother surface side of said structure body; and a transmutation materialbinding process that binds the material that undergoes nuclidetransmutation to the one surface of said structure body.
 8. A nuclidetransmutation method according to claim 7, wherein said transmutationmaterial binding process includes either a transmutation materiallamination process that laminates said material that undergoes nuclidetransmutation on the one surface of said structure body, or atransmutation material supply process that exposes the one surface ofsaid structure body to a gas or liquid that includes said material thatundergoes nuclide transmutation.
 9. A nuclide transmutation methodaccording to claim 7, wherein said transmutation material bindingprocess binds said material that undergoes nuclide transmutation to theone surface of said structure body.